-
Cytokine Jun 2024Laryngopharyngeal reflux (LPR) is one of the most common disorders in otorhinolaryngology, affecting up to 10% of outpatients visiting otolaryngology departments. In...
BACKGROUND
Laryngopharyngeal reflux (LPR) is one of the most common disorders in otorhinolaryngology, affecting up to 10% of outpatients visiting otolaryngology departments. In addition, 50% of hoarseness cases are related to LPR. Pepsin reflux-induced aseptic inflammation is a major trigger of LPR; however, the underlying mechanisms are unclear. The nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome has become an important bridge between stimulation and sterile inflammation and is activated by intracellular reactive oxygen species (ROS) in response to danger signals, leading to an inflammatory cascade. In this study, we aimed to determine whether pepsin causes LPR-associated inflammatory injury via mediating inflammasome activation and explore the potential mechanism.
METHODS
We evaluated NLRP3 inflammasome expression and ROS in the laryngeal mucosa using immunofluorescence and immunohistochemistry. Laryngeal epithelial cells were exposed to pepsin and analyzed using flow cytometry, western blotting, and real-time quantitative PCR to determine ROS, NLRP3, and pro-inflammatorycytokine levels.
RESULTS
Pepsin expression was positively correlated with ROS as well as caspase-1 and IL-1β levels in laryngeal tissues. Intracellular ROS levels were elevated by increased pepsin concentrations, which were attenuated by apocynin (APO)-a ROS inhibitor-in vitro. Furthermore, pepsin significantly induced the mRNA and protein expression of thioredoxin-interacting protein, NLRP3, caspase-1, and IL-1β in a dose-dependent manner. APO and the NLRP3 inhibitor, MCC950, inhibited NLRP3 inflammasome formation and suppressed laryngeal epithelial cell damage.
CONCLUSION
Our findings verified that pepsin could regulate the NLRP3/IL-1β signaling pathway through ROS activation and further induce inflammatory injury in LPR. Targeting the ROS/NLRP3 inflammasome signaling pathway may help treat patients with LPR disease.
Topics: Humans; NLR Family, Pyrin Domain-Containing 3 Protein; Inflammasomes; Reactive Oxygen Species; Pepsin A; Laryngopharyngeal Reflux; Signal Transduction; Inflammation; Caspase 1; Interleukin-1beta
PubMed: 38471420
DOI: 10.1016/j.cyto.2024.156568 -
Scientific Reports Jan 2023Protein hydrolysates from dietary sources possess many physiological and biological properties. Artocarpus altilis is an evergreen multipurpose plant with many benefits....
Protein hydrolysates from dietary sources possess many physiological and biological properties. Artocarpus altilis is an evergreen multipurpose plant with many benefits. Therefore, this study evaluates in vitro antioxidant and anti-inflammatory properties of A. altilis protein hydrolysates. Protein was isolated from A. altilis and hydrolysed with pepsin and trypsin separately using different enzyme: substrate ratios (1:8, 1:16, 1:32). Antioxidant properties investigated included Fe-chelating, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and hydrogen peroxide radical scavenging activities. Anti-inflammatory activities were determined using effects on hypotonic solution-induced cell lysis on red blood cell membrane stabilisation and heat-induced protein denaturation. The degree of hydrolysis of trypsin hydrolysate increased with increasing enzyme-substrate ratio, while pepsin hydrolysate decreased as the enzyme-substrate ratio increased. The dominant amino acids in A. altilis protein and hydrolysates were glutamate, aspartate and leucine. Protein hydrolysates obtained from pepsin and trypsin digestion had DPPH scavenging abilities of 43.0 ± 0.01% and 22.2 ± 0.01%, respectively. However, trypsin-hydrolysed protein had a high Fe-chelating ability, while pepsin-hydrolysed protein had high hydrogen peroxide scavenging ability. Trypsin-hydrolysed protein showed good membrane stability and inhibition of protein denaturation. The results indicated that A. altilis protein hydrolysates possess significant antioxidant and anti-inflammatory effects and can further lend support to food industries as functional foods.
Topics: Antioxidants; Artocarpus; Protein Hydrolysates; Fruit; Pepsin A; Trypsin; Hydrogen Peroxide; Parkinson Disease; Fabaceae
PubMed: 36707546
DOI: 10.1038/s41598-023-28684-z -
European Archives of... Jun 2022To explore the role played by Glut-1 and H/K-ATPase in pepsin-induced, mouse laryngeal epithelial proliferation, growth, and development.
PURPOSE
To explore the role played by Glut-1 and H/K-ATPase in pepsin-induced, mouse laryngeal epithelial proliferation, growth, and development.
METHODS
We established a mouse model of laryngopharyngeal reflux and measured Glut-1 and H/K-ATPase expression levels in mouse laryngeal epithelium treated with artificial gastric juice containing pepsin.
RESULTS
Artificial pepsin-containing gastric juice induced significant hyperplastic changes in mouse laryngeal epithelium compared to control mice at 15, 30, and 45 days. Inhibition of Glut-1 expression by 2-DG significantly suppressed such hyperplasia compared to mice exposed to artificial gastric juice containing pepsin at 15, 30, and 45 days. After treatment with pepsin-containing artificial gastric juice, RT-PCR and Western blotting showed that the levels of Glut-1 and H/K-ATPase α, β increased significantly.
CONCLUSIONS
Pepsin-containing artificial gastric juice promoted mouse laryngeal epithelial hyperplasia associated with abnormal expression of Glut-1 and H/K-ATPase α, β.
Topics: Adenosine Triphosphatases; Animals; Humans; Hyperplasia; Laryngeal Mucosa; Laryngopharyngeal Reflux; Mice; Pepsin A
PubMed: 35083516
DOI: 10.1007/s00405-021-07221-6 -
EFSA Journal. European Food Safety... Jun 2022The food enzyme containing chymosin (EC 3.4.23.4) and pepsin A (EC 3.4.23.1) is prepared from the abomasum of calves by RENCO New Zealand. The food enzyme is intended to...
The food enzyme containing chymosin (EC 3.4.23.4) and pepsin A (EC 3.4.23.1) is prepared from the abomasum of calves by RENCO New Zealand. The food enzyme is intended to be used in milk processing for cheese production. As no concerns arise from the animal source of the food enzyme or from its manufacture and based on the history of safe use and consumption, the Panel considered that toxicological data were not required, and the estimation of dietary exposure was unnecessary. On the basis of literature data, the Panel considered that the risk of allergic sensitisation and elicitation reactions by dietary exposure could not be excluded, but the likelihood for this to occur was considered to be low. The Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
PubMed: 35765379
DOI: 10.2903/j.efsa.2022.7361 -
Microbiology Spectrum Aug 2022Acid tolerance is an important feature of probiotic development. It is one of the factors underlying the beneficial effects of probiotics in the intestine. However, the...
Acid tolerance is an important feature of probiotic development. It is one of the factors underlying the beneficial effects of probiotics in the intestine. However, the methods used by different researchers to test acid tolerance vary, causing confusion in the interpretation of the results. Therefore, in this study, we determine the optimal conditions for the acid tolerance test using response surface methodology. The factors of pH (2.5 to 3.5), exposure time (1 to 2 h), and pepsin (presence or absence) were used as independent variables, and the survival rates of seven strains (Lacticaseibacillus casei KACC 12413, Lactiplantibacillus plantarum KACC 15357, Limosilactobacillus fermentum KACC 11441, WCFS1, Lacticaseibacillus rhamnosus GG, KCTC 21024, and WiKim 0112) known to have probiotic properties were used as dependent variables. The results of the analysis of variance (ANOVA) indicated that the pH value and exposure time in acidic environments significantly affected the acid tolerance test model, and their interaction also had an effect ( < 0.05). Using the ANOVA results, the condition of the acid tolerance test was optimized with a target of an 85% survival rate for each strain. The optimized conditions of the acid tolerance test were as follows: pH 2.92, exposure time of 1.73 h, and presence of pepsin and pH 3, exposure time of 1.98 h, and absence of pepsin. These results can optimize strain selection with rigorous acid tolerance without confusion by unifying the conditions for the acid tolerance test. The acid tolerance test, which is the first step in selecting probiotics, is not standardized and can often cause confusion in the interpretation of results. Thus, in the present study, we optimized the conditions for the acid tolerance test using response surface methodology. These optimized conditions can be used to screen for strains with acid tolerance.
Topics: Intestines; Lactobacillaceae; Lactobacillus plantarum; Pepsin A; Probiotics
PubMed: 35876583
DOI: 10.1128/spectrum.01625-22 -
World Journal of Gastroenterology May 2024Heartburn is a common symptom shared by both gastroesophageal reflux disease (GERD) and functional heartburn (FHB), which can make it challenging to differentiate...
Heartburn is a common symptom shared by both gastroesophageal reflux disease (GERD) and functional heartburn (FHB), which can make it challenging to differentiate between the two conditions. However, examining oral manifestations of GERD can be a cost-effective and readily available method to aid in this differentiation process. It may serve as a valuable tool in distinguishing GERD from FHB.
Topics: Humans; Gastroesophageal Reflux; Saliva; Heartburn; Pepsin A; Diagnosis, Differential; Biomarkers
PubMed: 38817654
DOI: 10.3748/wjg.v30.i19.2612 -
Clinical Kidney Journal Jan 2021The hepatokine fetuin-A, released by the human liver, promotes pro-inflammatory effects of perivascular fat. The involvement of inflammation in type 2 diabetes mellitus...
BACKGROUND
The hepatokine fetuin-A, released by the human liver, promotes pro-inflammatory effects of perivascular fat. The involvement of inflammation in type 2 diabetes mellitus (T2DM) can affect the kidney and contribute to the development of diabetic kidney disease. Therefore we examined the association of urinary fetuin-A protein fragments with renal damage in T2DM patients.
METHODS
Urinary peptides of 1491 individuals using proteome data available from the human urine proteome database were analysed. Prediction of proteases involved in urinary peptide generation was performed using the Proteasix tool.
RESULTS
We identified 14 different urinary protein fragments that belong to the region of the connecting peptide (amino acid 301-339) of the total fetuin-A protein. Calpains (CAPN1 and CAPN2), matrix metalloproteinase and pepsin A-3 were identified as potential proteases that were partially confirmed by previous studies. Combined fetuin-A peptides (mean of amplitudes) were significantly increased in T2DM patients with kidney disease and to a lesser extent with cardiovascular risk. Furthermore, fetuin-A peptide levels displayed a significant negative correlation with baseline estimated glomerular filtration rate (eGFR) values ( = -0.316, P < 0.0001) and with the slope (%) of eGFR per year ( = -0.096, P = 0.023). A multiple regression model including fetuin-A peptide and albuminuria resulted in a significantly improved correlation with eGFR ( = -0.354, P < 0.0001) compared with albuminuria, indicating an added value of this novel biomarker.
CONCLUSIONS
The urinary proteome analysis demonstrated the association of fetuin-A peptides with impaired kidney function in T2DM patients. Furthermore, fetuin-A peptides displayed early signs of kidney damage before albuminuria appeared and therefore can be used as markers for kidney disease detection.
PubMed: 33564428
DOI: 10.1093/ckj/sfaa176 -
Environmental Pollution (Barking, Essex... Oct 2023Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food...
Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food proteins are still unknown. In this study, the interactions between pepsin and polystyrene (PS) MPs were evaluated by investigating enzyme activity and conformation in a simulated human gastric environment in the presence or absence of PS MPs. The impact on food digestion was also assessed by monitoring the kinetics of protein hydrolysis through static in vitro gastric digestion of cow's milk contaminated with PS. The binding of pepsin to PS showed that the surface chemistry of MPs dictates binding affinity. The key contributor to pepsin adsorption seems to be π-π interactions between the aromatic residues and the PS phenyl rings. During quick exposure (10 min) of pepsin to increasing concentrations (222, 2219, 22188 particles/mL) of 10 μm PS (PS10) and 100 μm PS (PS100), total enzymatic activities were not affected remarkably. However, upon prolonged exposure at 1 and 2 h, preferential binding of pepsin to the small, low zeta-potential PS caused structural changes in the protein which led to a significant reduction of its activity. Digestion of cow's milk mixed with PS10 resulted in transient accumulation of larger peptides (10-35 kDa) and reduced bioavailability of short peptides (2-9 kDa) in the gastric phase. This, however, was only observed at extremely high PS10 concentration (0.3 mg/mL or 5.46E+05 particles/mL). The digestion of milk peptides, bound preferentially over pepsin within the hard corona on the PS10 surface, was delayed up to 15 min in comparison to bulk protein digestion. Intact caseins, otherwise rapidly digested, remained bound to PS10 in the hard corona for up to 15 min. This work presents valuable insights regarding the interaction of MPs, food proteins, and pepsin, and their dynamics during gastric digestion.
Topics: Humans; Milk Proteins; Pepsin A; Microplastics; Polystyrenes; Plastics; Peptides; Caseins; Allergens; Digestion
PubMed: 37516294
DOI: 10.1016/j.envpol.2023.122282 -
PloS One 2023Today, breast cancer and infectious diseases are very worrying that led to a widespread effort by researchers to discover natural remedies with no side effects to fight...
Today, breast cancer and infectious diseases are very worrying that led to a widespread effort by researchers to discover natural remedies with no side effects to fight them. In the present study, we isolated camel milk protein fractions, casein and whey proteins, and hydrolyzed them using pepsin, trypsin, and both enzymes. Screening of peptides with anti-breast cancer and antibacterial activity against pathogens was performed. Peptides derived from whey protein fraction with the use of both enzymes showed very good activity against MCF-7 breast cancer with cell viability of 7.13%. The separate use of trypsin and pepsin to digest whey protein fraction yielded peptides with high antibacterial activity against S. aureus (inhibition zone of 4.17 ± 0.30 and 4.23 ± 0.32 cm, respectively) and E. coli (inhibition zone of 4.03 ± 0.15 and 4.03 ± 0.05 cm, respectively). Notably, in order to identify the effective peptides in camel milk, its protein sequences were retrieved and enzymatically digested in silico. Peptides that showed both anticancer and antibacterial properties and the highest stability in intestinal conditions were selected for the next step. Molecular interaction analysis was performed on specific receptors associated with breast cancer and/or antibacterial activity using molecular docking. The results showed that P3 (WNHIKRYF) and P5 (WSVGH) peptides had low binding energy and inhibition constant so that they specifically occupied active sites of protein targets. Our results introduced two peptide-drug candidates and new natural food additive that can be delivered to further animal and clinical trials.
Topics: Animals; Camelus; Protein Hydrolysates; Escherichia coli; Molecular Docking Simulation; Pepsin A; Staphylococcus aureus; Trypsin; Whey Proteins; Neoplasms; Peptides; Anti-Bacterial Agents
PubMed: 37437001
DOI: 10.1371/journal.pone.0288260 -
Nature Microbiology Aug 2019Pili on the surface of Sulfolobus islandicus are used for many functions, and serve as receptors for certain archaeal viruses. The cells grow optimally at pH 3 and...
Pili on the surface of Sulfolobus islandicus are used for many functions, and serve as receptors for certain archaeal viruses. The cells grow optimally at pH 3 and ~80 °C, exposing these extracellular appendages to a very harsh environment. The pili, when removed from cells, resist digestion by trypsin or pepsin, and survive boiling in sodium dodecyl sulfate or 5 M guanidine hydrochloride. We used electron cryo-microscopy to determine the structure of these filaments at 4.1 Å resolution. An atomic model was built by combining the electron density map with bioinformatics without previous knowledge of the pilin sequence-an approach that should prove useful for assemblies where all of the components are not known. The atomic structure of the pilus was unusual, with almost one-third of the residues being either threonine or serine, and with many hydrophobic surface residues. While the map showed extra density consistent with glycosylation for only three residues, mass measurements suggested extensive glycosylation. We propose that this extensive glycosylation renders these filaments soluble and provides the remarkable structural stability. We also show that the overall fold of the archaeal pilin is remarkably similar to that of archaeal flagellin, establishing common evolutionary origins.
Topics: Archaea; Archaeal Proteins; Cryoelectron Microscopy; Fimbriae Proteins; Glycosylation; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Pepsin A; Protein Conformation; Protein Stability; Sequence Analysis, Protein; Sulfolobus; Trypsin
PubMed: 31110358
DOI: 10.1038/s41564-019-0458-x